import java.io.File;
import java.io.IOException;
import java.util.StringTokenizer;

import org.apache.commons.io.FileUtils;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

public class MRV2Main {

  public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable> {

    private final static IntWritable one = new IntWritable(1);

    private Text word = new Text();

    /**

     * 

     */
    public void map(Object key, Text value, Context context) throws IOException,
        InterruptedException {

      StringTokenizer itr = new StringTokenizer(value.toString());
      while (itr.hasMoreTokens()) {
        word.set(itr.nextToken());
        context.write(word, one);
      }
    }
  }

  public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> {
    private IntWritable result = new IntWritable();

    public void reduce(Text key, Iterable<IntWritable> values, Context context)
        throws IOException, InterruptedException {
      int sum = 0;
      for (IntWritable val : values) {
        sum += val.get();
      }
      result.set(sum);
      context.write(key, result);
    }
  }

  public static void main(String[] args) throws Exception {
    System.setProperty("hadoop.home.dir", "E:/opensource/hadoop-2.2.0");
    System.load("E:/opensource/hadoop-2.2.0/bin/hadoop.dll");

    File file = new File("output");
    if (file.exists()) {
      FileUtils.deleteDirectory(file);
    }

    Job job = Job.getInstance();
    job.setJarByClass(MRV2Main.class);
    job.setMapperClass(TokenizerMapper.class);
    job.setCombinerClass(IntSumReducer.class);
    job.setReducerClass(IntSumReducer.class);
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(IntWritable.class);
    FileInputFormat.addInputPath(job, new Path("input"));
    FileOutputFormat.setOutputPath(job, new Path("output"));
    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }

}